/* --------------------------------------------------------------------------
 * gin.h
 *	  Public header file for Generalized Inverted Index access method.
 *
 *	Copyright (c) 2006-2014, PostgreSQL Global Development Group
 *
 *	src/include/access/gin.h
 * --------------------------------------------------------------------------
 */
#ifndef GIN_H
#define GIN_H

#include "access/xlogreader.h"
#include "lib/stringinfo.h"
#include "storage/buf/block.h"
#include "utils/relcache.h"

/*
 * amproc indexes for inverted indexes.
 */
#define GIN_COMPARE_PROC 1
#define GIN_EXTRACTVALUE_PROC 2
#define GIN_EXTRACTQUERY_PROC 3
#define GIN_CONSISTENT_PROC 4
#define GIN_COMPARE_PARTIAL_PROC 5
#define GIN_TRICONSISTENT_PROC 6
#define GINNProcs 6

/*
 * searchMode settings for extractQueryFn.
 */
#define GIN_SEARCH_MODE_DEFAULT 0
#define GIN_SEARCH_MODE_INCLUDE_EMPTY 1
#define GIN_SEARCH_MODE_ALL 2
#define GIN_SEARCH_MODE_EVERYTHING 3 /* for internal use only */

/*
 * GinStatsData represents stats data for planner use
 */
typedef struct GinStatsData {
    BlockNumber nPendingPages;
    BlockNumber nTotalPages;
    BlockNumber nEntryPages;
    BlockNumber nDataPages;
    int64 nEntries;
    int32 ginVersion;
} GinStatsData;

/*
 * A ternary value used by tri-consistent functions.
 *
 * For convenience, this is compatible with booleans. A boolean can be
 * safely cast to a GinTernaryValue.
 */
typedef char GinTernaryValue;

#define GIN_FALSE 0 /* item is not present / does not match */
#define GIN_TRUE 1  /* item is present / matches */
#define GIN_MAYBE                                   \
    2 /* don't know if item is present / don't know \
       * if matches */

#define DatumGetGinTernaryValue(X) ((GinTernaryValue)(X))
#define GinTernaryValueGetDatum(X) ((Datum)(X))
#define PG_RETURN_GIN_TERNARY_VALUE(x) return GinTernaryValueGetDatum(x)

/* ginutil.c */
extern void ginGetStats(Relation index, GinStatsData *stats);
extern void ginUpdateStats(Relation index, const GinStatsData *stats);

/* ginxlog.c */
extern void gin_redo(XLogReaderState *record);
extern void gin_desc(StringInfo buf, XLogReaderState *record);
extern const char* gin_type_name(uint8 subtype);
extern void gin_xlog_startup(void);
extern void gin_xlog_cleanup(void);
extern bool IsGinVacuumPages(XLogReaderState *record);

typedef char GinLogicValue;
#define DatumGetGinLogicValue(X) ((GinLogicValue)(X))
#define GinLogicValueGetDatum(X) ((Datum)(X))
#define PG_RETURN_GIN_LOGIC_VALUE(x) return GinLogicValueGetDatum(x)

#endif /* GIN_H */
